Both incandescent and fluorescent lamps are commonly used in residential, commercial, and institutional applications. However, both types of lighting solutions suffer from certain disadvantages. For example, incandescent lamps convert approximately 3% of electrical power consumed into usable light, while the remaining 97% of power may be wasted as heat. Compared to an incandescent lamp, a fluorescent lamp converts electrical power into useful light more efficiently, delivers a significantly longer useful life, and presents a more diffuse and physically larger light source. However, fluorescent lamps are typically more expensive to install and operate than an incandescent lamp because of the requirement for a ballast to regulate the electrical current. Many fluorescent lamps have poor color temperature, resulting in a less aesthetically pleasing light. Also, if a fluorescent lamp that uses mercury vapor is broken, a small amount of mercury (classified as hazardous waste) can contaminate the surrounding environment.
Digital lighting technologies such as light-emitting diodes (LEDs) offer significant advantages over legacy incandescent and fluorescent lamps. These advantages include but are not limited to better lighting quality, longer operating life, and lower energy consumption. Consequently, a market exists for LED-based retrofit alternatives to legacy lighting fixtures. However, a number of installation challenges and costs are associated with replacing legacy lamps with LED illumination devices. The challenges may, for example, include light output, thermal management, and ease of installation. The costs, which are similarly understood by those skilled in the art, typically stem from a need to replace or reconfigure fixtures configured to support legacy lamps to support LEDs instead.
By the very nature of their design and operation, LEDs have a directional light output. Consequently, the light emitted by an LED may not have the nearly omni-directional and uniform light distribution of incandescent and fluorescent lamps. Although multiple LEDs can be used in a single lamp, lighting solutions employing LEDs do not have light distribution properties approximating or equaling the dispersion properties of traditional lamps.
Another challenge inherent to operating LEDs is heat. Thermal management describes a system's ability to draw heat away from the LED, either passively or actively. LEDs may suffer damage and decreased performance when operating in high-heat environments. Moreover, when operating in a confined environment, the heat generated by an LED, and its attending circuitry itself, can cause damage to the LED. Heat sinks are well known in the art and have been effectively used to provide cooling capacity to maintain an LED-based light bulb within a desirable operating temperature. However, heat sinks can sometimes negatively impact the light distribution properties of the light fixture, resulting in non-uniform distribution of light about the light fixture.
Power supply requirements of LED-based lighting systems can complicate installation of LEDs as a retrofit to existing light fixtures. LEDs are low-voltage light sources that require constant DC voltage or current to operate optimally, and therefore must be carefully regulated. Too little current and voltage may result in little or no light. Too much current and voltage can damage the light-emitting junction of the LED. LEDs are commonly supplemented with individual power adapters to convert AC power to the proper DC voltage, and to regulate the current flowing through during operation to protect the LEDs from line-voltage fluctuations.
Supporting mechanical attachment to a wide variety of existing light fixture types also complicates installation of retrofit lamps that employ LEDs. Because the retrofit lamp often does not match the form factor of the light source being replaced, alternative attachment mechanisms may be required. For example, mechanical fasteners may be screwed into new holes that may be drilled into the existing fixture to attach the retrofit LED-based light source. However, limited access to fastener mounting points on the existing fixture, and/or the risk of damaging the existing fixture may discourage the use of mechanical fasteners. In an alternative example, adhesives may be used to attach the retrofit LED-based light source to the existing fixture. However, not all fixture surfaces are conducive to adhesive attachment, particularly under temperature cycling typical of an LED-based lamp.
A need exists for a retrofit lighting device that may be easily and inexpensively mounted within the volume of space available in a variety of commercially-available light fixture configurations, and that may deliver improved lighting quality compared to traditional incandescent and fluorescent lamps. More specifically, a need exists for a retrofit lighting solution that benefits from the advantages of digital lighting technology, and is designed for ease of installation as well as for manufacturing cost reduction. The lighting industry is experiencing advancements in LED applications, some of which may be pertinent to certain aspects of replacing legacy lamps.
U.S. Pat. No. 7,806,575 to Willwohl et al. is directed to a LED lighting module having an LED element, an electronic driver arrangement, and a heat sink shaped to form a casing for the electronic driver arrangement. However, the disclosure presumes the availability of a power source external to the LED lighting module that may supply power to the electronic driver arrangement. Furthermore, the disclosure recites front mounting (rather than base mounting) that positions the LED lighting module to protrude through an opening in a reflector casing of a lighting assembly.
U.S. Pat. No. 6,641,283 to Bohler discloses an LED puck light having a mounting base and an LED module enclosing lighting components and circuitry. The LED module may include a fixing apparatus for attaching the module to a corresponding attachment apparatus on the mounting base. For example, the fixing apparatus may be a magnet, and the attachment apparatus may be an oppositely-charged magnet pole. However, the disclosed LED puck light offers no thermal management solution such as a heat sink.
U.S. Pat. No. 8,172,436 to Coleman et al. discloses an LED-based auxiliary puck light with a base and a pivoting head. A magnet affixed to the base may be strong enough to securely and fixedly hold the auxiliary puck light on a magnetic surface. However, like the Bohler reference, the Coleman disclosure offers no thermal management solution such as a heat sink.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.